面试题66. 构建乘积数组

Posted 2020-12-15 ocpc

题目：

 

 

解答：

 

 

 1 class Solution {
 2 public:
 3     vector<int> constructArr(vector<int>& a) 、
 4     {
 5         int n = a.size();
 6         vector<int> ret(n, 1);
 7         
 8         int left = 1;
 9         for (int i = 0; i < n; i ++) 
10         {
11             ret[i] = left;
12             left = left * a[i];
13         } 
14 
15         int right = 1;
16         for (int i = n-1; i >= 0; i --) 
17         {
18             ret[i] *= right;
19             right *= a[i];
20         }
21         return ret;
22     }
23 };